The practice of deadheading is to prevent the plant from setting seed so that it keeps blooming…so by definition, probably not. Typically with annuals, the seed heads need time on the plant to develop into viable seeds and dry out enough. The flowers with petals still on will almost certainly not have viable seed. Some of the dried out brown ones on the bottom? Maybe! You can crack them open over a piece of paper and see what you get.

If they’re actually dead, no. If they’re not, I’m not sure why you’d remove them in deadheading, but maybe. Worth a shot, at least.